Underwater Field Guide to Ross Island & McMurdo Sound, Antarctica, Volume 4: Echinodermata

Underwater Field Guide to Ross Island & McMurdo
Sound, Antarctica, Volume 4: Echinodermata
seastars, urchins, brittle stars, sea cucumbers, crinoids

Peter Brueggeman

Photographs: Isidro Bosch, Peter Brueggeman, Rod Budd/Antarctica New
Zealand, Kathleen Conlan/Canadian Museum of Nature, Paul Cziko, Paul
Dayton, Shawn Harper, Henry Kaiser/NSF, Adam G Marsh, Jim Mastro,

Bruce A Miller, Rob Robbins, Steve Rupp/NSF, M Dale Stokes, & Norbert

N
Ross Island & McMurdo Sound

The National Science Foundation's Office of Polar Programs sponsored Norbert Wu on an Artist's
and Writer's Grant project, in which Peter Brueggeman participated. One outcome from Wu's
endeavor is this Field Guide, which builds upon principal photography by Norbert Wu, with photos
from other photographers, who are credited on their photographs and above. This Field Guide aims
to facilitate underwater/topside field identification from visual characters. Most organisms were
identified from photographs with no specimen collection, so there can be uncertainty with these
identifications.

Seastar ID advisors included John H. Dearborn
Taxonomic names checked in Zoological Record and World Register of Marine Species: October 2024

Keywords; Antarctic, Antarctica, field guide, marine, Ross Island, McMurdo Sound, echinodermata, echinoderm, seastar, starfish, sea urchin, brittle star, sea cucumber,
crinoid

© 2024, first edition published in 1998. Text © Peter Brueggeman. Photographs © Isidro Bosch, Peter Brueggeman, Rod Budd/Antarctica New Zealand Pictorial Collection
159679 2001-2002, Kathleen Conlan/Canadian Museum of Nature, Paul Cziko, Paul Dayton, Shawn Harper, Henry Kaiser/NSF, Adam G Marsh, Jim Mastro, Bruce A
Miller, Rob Robbins, Steve Rupp/NSF, M Dale Stokes, & Norbert Wu. Photographs may not be used in any form without the express written permission of the
photographers. Norbert Wu does not grant permission for uncompensated use of his photos; see www.norbertwu.com

seastar Acodontaster conspicuus

seastar Acodontaster hodgsoni

seastar Cuenotaster involutus

seastar Diplasterias brucei

seastar Lophaster gaini

seastar Macroptychaster accrescens

astropectinid sea star, probably Macroptychaster accrescens or
Leptychaster sp.

seastar Notasterias armata

seastar Odontaster spp.

seastar Odontaster validus

seastar Perknaster aurorae

seastar Perknaster fuscus

seastar Glabraster antarctica

seastar Psilaster charcoti

possibly the seastar Preraster affinis

heart urchin Abatus sp.

@ M Dale stokes

pencil urchin Ctenocidaris perrieri

sea urchin Sterechinus neumayeri

brittle star Astrotoma agassizii

brittle star Ophiacantha antarctica

brittle star Ophionotus victoriae

brittle star Ophioplinthus sp., probably Ophioplinthus gelida

brittle star Ophiosparte gigas

sea cucumber Staurocucumis liouvillei

sea cucumber Staurocucumis turqueti

sea cucumber Bathyplotes bongraini

sea cucumber Cucumaria spp.

sea cucumber Echinopsolus acanthocola

sea cucumber Heterocucumis steineni

@® Peter Urueqgeman

sea cucumber, group Aspidochirotida

crinoid Promachocrinus kerguelensis

seastar Acodontaster conspicuus

A. conspicuus

Acodontaster conspicuus is
found throughout Antarctica
and the Antarctic Peninsula,
South Shetland Islands, South
Orkney Islands, South
Sandwich Islands, South
Georgia Island, Bouvet Island,
and Falkland Islands between 0
and 761+ meters depth 3,5 ,6,7,3}.

Acodontaster conspicuus has
been collected at sizes up to
fourteen centimeters in radius
from its center to the tip of an
arm [4,6].

; The color of Acodontaster

conspicuus (shown on the
right compared to A. hodgsoni

| on the left) has been recorded
__ as pink, orange, pale orange,
) brown, and brownish yellow

and it may be yellowish
towards the edges {4,6}.

Acodontaster conspicuus has a
flattened disc with arms wide
at their base and narrowing
quickly with a thin edge {«).

10

One way to distinguish Acodontaster conspicuus from
the other Ross Sea Acodontaster species is by the
presence of pincer-like pedicellariae on the underside
of Acodontaster conspicuus {4}.

; fe A preserved specimen of Acodontaster conspicuus shows
the pincer-like pedicellariae with greater clarity (4).

Pedicellaria keep the seastar's body surface clear of

encrusting organisms by pinching or cutting their settling
larvae.

11

©Norbert Wu

Showing an Acodontaster sp. here, Acodontaster conspicuus is a predator of rossellid sponges and the sponges
Homaxinella balfourensis, Anoxycalyx (Scolymastra) joubini (shown here), Antarctotetilla leptoderma, Haliclona
scotti, Mycale (Oxymycale) acerata, and Kirkpatrickia variolosa {1,2}. Observations suggest that a single A.
conspicuus does not stay long on the sponge Anoxycalyx (Scolymastra) joubini but several accumulate, do not
leave, and consume enough of the sponge to kill it (2).

12

©Norbert Wu

Here’s a gang attack on an Acodontaster sp. by the predatory seastar Odontaster validus. Predators of Acodontaster
conspicuus include the seastar Odontaster validus (shown here), the nemertean proboscis worm Parborlasia
corrugatus (in foreground), and the anemone Urticinopsis antarcticus {2,31}. Acodontaster conspicuus would reach
population densities destroying the sponge community if not kept in check by Odontaster validus which preys upon
the larvae, young and adult A. conspicuus {2}. A single Odontaster validus climbs up onto an Acodontaster
conspicuus armray, everts its stomach, and digests a hole into it. An attack by a single Odontaster validus isn't fatal
but nearby O. validus probably respond to the release of Acodontaster conspicuus coelomic fluid and join the attack
[2]:

13

QNorbert

Showing an Acodontaster sp. here, a gang attack eventually slows the larger Acodontaster conspicuus seastar's
movement, more Odontaster validus join the attack, and the large nemertean proboscis worm Parborlasia
corrugatus joins in as well. A. conspicuus seastars can become completely buried under high piles of attacking
Odontaster validus seastars and Parborlasia corrugatus worms 2}.

References: 1: Science 245:1484-1486, 1989; 2: Ecological Monographs 44(1):105-128, 1974 (P. Dayton, personal communication, 2015: Haliclona dancoi observations are
corrected to H. scotti; Rossella racovitzae observations are corrected to R. podagrosa); 3: Adaptations within Antarctic Ecosystems: Proceedings of the Third SCAR
Symposium on Antarctic Biology. George A. Llano, ed. Washington: Smithsonian Institution; Houston, Tex.: distributed by Gulf Pub. Co., 1977. pp.293-326; 4: The Fauna
of the Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial Research Bulletin 151, New Zealand Oceanographic Institute Memoir
21, 1963; 5: Polar Biology 20(4):229-247, 1998; 6: Equinodermos Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la Peninsula Antartica. I Bernasconi.
Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Zoologia (aka Ciencias
Zoologicas) 9(10):211-281 and plates, 1970; 7: U.S. National Museum of Natural History, Dept of Zoology, Invertebrate Zoology, Invertebrate Zoology Collections
database; 8: Amazing Antarctic asteroids: a guide to the starfish of the Ross Sea. Kate Neill et al. NIWA, New Zealand, Version 1, 2016 www.niwa.co.nz/coasts-and-
oceans/marine-identification-guides-and-fact-sheets/amazing-antarctic-asteroids

14

seastar Acodontaster hodgsoni

Acodontaster hodgsoni is found throughout
Antarctica, the Antarctic Peninsula, South
Shetland Islands, South Orkney Islands, South
Sandwich Islands, South Georgia Island,
Bouvet Island, Crozet Islands, Heard Island,
Kerguelen Islands, Prince Edward Islands,

9 9'F Vy

Acodontaster hodgsoni has been collected
at sizes up to twenty centimeters in radius
from its center to the tip of an arm /2}.

15

A. conspicuus

Acodontaster hodgsoni is shown on
the left compared to Acodontaster
conspicuus on the right.

Acodontaster hodgsoni is a predator
of the sponges Haliclona scotti,
Calyx shackletoni, rossellid
sponges, and Hemigellius fimbriatus

[1].

As shown here, Acodontaster
hodgsoni lacks the pincer-like
pedicellariae alongside its
underside spines, which are present
on Acodontaster conspicuus {2}.

Predators of Acodontaster hodgsoni include the seastar Odontaster validus, the nemertean worm Parborlasia

corrugatus, and the anemone Urticinopsis antarcticus {1}.

References: 1: Ecological Monographs 44(1):105-128, 1974 (P. Dayton, personal communication, 2015: Haliclona dancoi observations are corrected to H. scotti; Gellius
tenella corrected to Hemigellius fimbriatus; Rossella racovitzae observations are corrected to R. podagrosa); 2: The Fauna of the Ross Sea, Part 3, Asteroidea. HES Clark.
New Zealand Department of Scientific and Industrial Research Bulletin 151, New Zealand Oceanographic Institute Memoir 21, 1963; 3: Bulletin de l'Institut Royal des
Sciences Naturelles de Belgique. Biologie 63:175-184, 1993; 4: Discovery Reports 20:115, 1941; 5: U.S. National Museum of Natural History, Dept of Zoology, Invertebrate
Zoology, Invertebrate Zoology Collections database; 6: Polar Biology 38:799-813, 2015; 7: Amazing Antarctic asteroids: a guide to the starfish of the Ross Sea. Kate Neill et
al. NIWA, New Zealand, Version 1, 2016 www.niwa.co.nz/coasts-and-oceans/marine-identification-guides-and-fact-sheets/amazing-antarctic-asteroids

16

seastar Cuenotaster involutus

@Canadian Museuii"ot) Ale oa

Cuenotaster involutus is found throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, South
Orkney Islands, South Georgia Island, Shag Rocks, and Bouvet Island from 0 to 794 meters depth [1,2,4,5,6,7].

The disc of C. involutus may be flat or slightly convex and is depressed between arms [3]. The arms of Cuenotaster
involutus are long, slender, flexible, convex-surfaced, and blunt-tipped and may sometimes be coiled ventrally [3,4).

Cuenotaster involutus has been collected at sizes up eleven centimeters in radius from its center to the tip of an arm
[23,5]

17

aNorbett

The color of Cuenotaster involutus includes pink-brick, grey-brown, yellowish brown, white, greenish gray, and
gray white [2,3,4,5).

Cuenotaster involutus has distinctive and unmistakeable bristling, and well-spaced rosette-like paxillae along the
disc and arms of Cuenotaster involutus (3,4,5}.

Cuenotaster involutus may be both an active predator and a scavenger [1).

References: 1: Adaptations within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A. Llano, ed. Washington: Smithsonian
Institution; Houston, Tex.: distributed by Gulf Pub. Co., 1977. pp.293-326; 2: Fauna der Antarktis. J Sieg & JW Wagele, eds. Berlin: P. Parey, 1990; 3: The Fauna of the
Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial Research Bulletin 151, New Zealand Oceanographic Institute Memoir 21,
1963; 4: Discovery Reports 20:69-306 and plates, 1940; 5: Equinodermos Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la Peninsula Antartica. I
Bernasconi. Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Zoologia (aka
Ciencias Zoologicas) 9(10):211-281 and plates, 1970; 6: Polar Biology 38:799-813, 2015; 7: Amazing Antarctic asteroids: a guide to the starfish of the Ross Sea. Kate Neill
et al. NIWA, New Zealand, Version 1, 2016 www.niwa.co.nz/coasts-and-oceans/marine-identification-guides-and-fact-sheets/amazing-antarctic-asteroids

18

seastar Diplasterias brucei

Diplasterias brucei is found throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, South
Orkney Islands, South Sandwich Islands, South Georgia Island (six-rayed forma), Tierra del Fuego, Crozet Islands,
Heard Island, Marion and Prince Edward Islands, from 0 to 752 meters depth [3,6,7,8,9,10,11,12}-

19

Diplasterias brucei color can be light blue-green on top with white spines and a whitish border to the disc and arms
with the arm tips blood-red; other recorded colors are pale grey to blue-grey, pale orange or pale blue-grey with a
red eye spot at each arm tip, light brown, creamy white with red blotches ,7,10}.

©Norbert Wu

The disc of Diplasterias brucei is small and convex; its arms taper gradually to blunt tips (7). Diplasterias brucei has
been collected at sizes up to 23.7 centimeters in radius from its center to the tip of an arm [6,7,10}.

21

These are juvenile
Diplasterias brucei.

22

@Norbert. Wu

As shown here, Diplasterias brucei specializes on molluscan prey; it is a significant predator of the bivalve mollusc
Limatula hodgsoni which can comprise almost all of its diet (2,3). Diplasterias brucei also eats the muricid gastropod
Trophonella longstaffi, and is a scavenger on dead material (2,3).

Diplasterias brucei is a prey item for the anemone Urticinopsis antarctica (2).

23

Here is Diplasterias brucei on anchor ice.

24

Here Diplasterias brucei is humped up and brooding its young in a pocket formed by the underside of its body [1).
Ripe females have been observed year-round |5}.

25

Closer view of the eggs being brooded by Diplasterias brucei, as seen from its underside, the ventral side of the
seastar.

Brood protection occurs quite commonly among Antarctic marine invertebrates (4).

©Bruce A Miller

This Diplasterias brucei is humped up and brooding its young.

21

Yolky eggs of Diplasterias brucei.

Brood protection helps larvae avoid the stresses of the environment and predation {4}. Brooding helps larvae avoid
the dangers of being eaten if the larvae were planktonic in a strong seasonal planktonic cycle as seen in Antarctic
waters [4).

References: 1: Ecological Monographs 44(1):105-128, 1974; 2: Antarctic Ecology, Volume 1. MW Holdgate, ed. NY: Academic Press, 1970. pp.244-258; 3: Adaptations
within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A. Llano, ed. Washington: Smithsonian Institution; Houston, Tex.:
distributed by Gulf Pub. Co., 1977. pp.293-326; 4: Adaptations within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A.
Llano, ed. Washington: Smithsonian Institution; Houston, Tex.: distributed by Gulf Pub. Co., 1977. pp.135-157; 5: Marine Biology 104: 41-46, 1990; 6: Fauna der Antarktis.
J Sieg & JW Wagele, eds. Berlin: P. Parey, 1990; 7: The Fauna of the Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial
Research Bulletin 151, New Zealand Oceanographic Institute Memoir 21, 1963; 8: AM Clark. B.A.N.Z. Antarctic Research Expedition 1929-1931. Reports, Series B
(Zoology and Botany) Volume 9, Asteroidea. Adelaide: BANZAR Expedition Committee, 1962; 9: Discovery Reports 20:69-306 and plates, 1940; 10: Equinodermos
Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la Peninsula Antartica. I Bernasconi. Revista del Museo Argentino de Ciencias Naturales "Bernardino
Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Zoologia (aka Ciencias Zoologicas) 9(10):211-281 and plates, 1970; 11: Polar Biology 41:2423-
2433, 2018; 12: Amazing Antarctic asteroids: a guide to the starfish of the Ross Sea. Kate Neill et al. NIWA, New Zealand, Version 1, 2016 www.niwa.co.nz/coasts-and-
oceans/marine-identification-guides-and-fact-sheets/amazing-antarctic-asteroids

28

seastar Lophaster gaini

Lophaster gaini is found throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, and Adelaide
Island, at depths from 23 to 578 meters 11,36). Lophaster gaini has been collected at sizes up to 17.5 centimeters in
radius from its center to the tip of an arm 11).

©Norbert Wu

Lophaster gaini has a broad disc which is slightly concave in the center; its arms are broad at the base and taper
evenly to blunt tips protected by small square plates [1}.

30

a1

‘ae Rt.
TARR

ee

One prey item of Lophaster gaini is the Antarctic scallop Adamussium colbecki {4}.

References: 1: The Fauna of the Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial Research Bulletin 151, New Zealand
Oceanographic Institute Memoir 21, 1963; 2: Isidro Bosch, 1999, personal communication; 3: Jim Mastro, personal communication, 1999 (New Harbor, 23 meters); 4:
Ecology of the Circumpolar Antarctic Scallop, Adamussium colbecki (Smith, 1902). Paul Arthur Berkman. Ph. D. Dissertation, University of Rhode Island, 1988; 5:
Echinodermes (Asteries, Ophiures et Echinides). R Koehler. Deuxieme Expedition Antarctique Francaise (1908-1910) commandee par le Dr Jean Charcot. Sciences
Naturelles. Documents Scientifiques. Paris: Masson et Cie, 1912; 6: Amazing Antarctic asteroids: a guide to the starfish of the Ross Sea. Kate Neill et al. NIWA, New
Zealand, Version 1, 2016 www.niwa.co.nz/coasts-and-oceans/marine-identification-guides-and-fact-sheets/amazing-antarctic-asteroids

seastar Macroptychaster accrescens

Macroptychaster accrescens color has been recorded as orange with darker brown transverse bands across the arms
and brown markings on the central disc ,1).

33

@Brtce A Miller

Macroptychaster accrescens has been collected at sizes up to 26 centimeters in radius from its center to the tip of an
arm [1].

Macroptychaster accrescens is uncommonly seen {4}.

34

Like other seastars in the Astropectinidae, Macroptychaster accrescens lacks sucking discs on its tube feet
indicating a preference for soft or muddy environments 11}.

@Bruce “A Miller

Macroptychaster accrescens is a predator of the seastar Odontaster validus, the sea urchin Sterechinus neumayeri,
gastropod molluscs, bivalves, and brittle stars (3,4).

Females of Macroptychaster accrescens are presumed to spawn their eggs by broadcasting them into the water
where they develop into non- feeding larvae [2). This pelagic (open ocean) non-feeding larval development is common
among McMurdo Sound seastars |2). Their larvae develop on stored yolk (lecithotrophic) which is probably an
adaptation to low food levels {2}. Seastars in temperate and tropical shallow waters typically have feeding larvae (2).

36

@Bruce ASMyliler

References: 1: The Fauna of the Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial Research Bulletin 151, New Zealand
Oceanographic Institute Memoir 21, 1963; 2: Marine Biology 104:41-46, 1990; 3: Ecological Monographs 44(1):105-128, 1974; 4: Adaptations within Antarctic
Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A. Llano, ed. Washington: Smithsonian Institution; Houston, Tex.: distributed by
Gulf Pub. Co., 1977. pp.293-326; 5: Equinodermos Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la Peninsula Antartica. I Bernasconi. Revista del
Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Zoologia (aka Ciencias Zoologicas)
9(10):211-281 and plates, 1970; 6: Amazing Antarctic asteroids: a guide to the starfish of the Ross Sea. Kate Neill et al. NIWA, New Zealand, Version 1, 2016
www.niwa.co.nz/coasts-and-oceans/marine-identification-guides-and-fact-sheets/amazing-antarctic-asteroids; 7: Polish Polar Research 18(2):107-117, 1997

37

astropectinid sea star, probably Macroptychaster accrescens or Leptychaster sp.

°

@Norbert Wu

These sea stars get very large and massive; this animal is probably a juvenile or young adult (1). Several characters
place it in the Leptychaster - Leptoptychaster - Macroptychaster complex which isn't taxonomically well-defined;
the species in these genera are fairly common on the Antarctic Shelf, but variable in their morphology {1}.

References: 1: John H. Dearborn, personal communication, 1999

38

seastar Notasterias armata

@Norbert Wu

Notasterias armata is found throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, Bouvet
Island, and Kerguelen Islands, from 15 to 752 meters depth [1,2,7,3).

39

@Shawn Harper

The color of Notasterias armata can be orange, creamy white, red, and mottled red with creamy areas (2,3).
Notasterias armata has been collected at sizes up to thirteen centimeters in radius from its center to the tip of an
arm 2,3]. The disc of Notasterias armata is small and its arms taper to blunt tips (2).

40

CON Fe bye FiaS ni

The diet of Notasterias armata includes the Antarctic scallop Adamussium colbecki (shown here) as well as the
bivalve Limatula hodgsoni {1,6}.

Notasterias armata broods its young in a brooding posture with a strongly convex disc and supporting itself on
bent arms [2]. Ripe females have been observed from August to February [5]. Brood protection occurs quite
commonly among Antarctic marine invertebrates ,4}. Brood protection helps larvae avoid the stresses of the
environment and predation {4}. Brooding helps larvae avoid the dangers of being eaten if the larvae were planktonic
in a strong seasonal planktonic cycle as seen in Antarctic waters [4}.

41

References: 1: Adaptations within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A. Llano, ed. Washington: Smithsonian
Institution; Houston, Tex.: distributed by Gulf Pub. Co., 1977. pp.293-326; 2: The Fauna of the Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand Department of
Scientific and Industrial Research Bulletin 151, New Zealand Oceanographic Institute Memoir 21, 1963; 3: Fauna der Antarktis. J Sieg & JW Wagele, eds. Berlin: P. Parey,
1990; 4: Adaptations within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A. Llano, ed. Washington: Smithsonian
Institution; Houston, Tex.: distributed by Gulf Pub. Co., 1977. pp.135-157; 5: Marine Biology 104: 41-46, 1990; 6: Ecology of the Circumpolar Antarctic Scallop,
Adamussium colbecki (Smith, 1902). Paul Arthur Berkman. Ph. D. Dissertation, University of Rhode Island, 1988; 7: Mitteilungen aus dem Hamburgischen Zoologischen
Museum und Institut 89:239- 259, 1992; 8: Amazing Antarctic asteroids: a guide to the starfish of the Ross Sea. Kate Neill et al. NIWA, New Zealand, Version 1, 2016
www.niwa.co.nz/coasts-and-oceans/marine-identification-guides-and-fact-sheets/amazing-antarctic-asteroids

42

seastar Odontaster spp.

@Peter Brueggeman

In the Ross Sea, an Odontaster seastar with yellow coloration can be Odontaster roseus, O. pearsei, O. validus, or
O. meridionalis [2,7,11,13,17,21]-

Odontaster roseus can be yellow, rosy, drab red, or tan /13.17].
Odontaster pearsei can be yellow or orange to tan {13,17}.

Odontaster validus varies widely in color and can be orange-yellow colored in addition to its characteristic dark
pink/red color ,17;. Colors of O. validus include dark brown, purple, purple-red, orange, orange-yellow, red-orange,
red, brick red, dark carmine, and pink [17,18,19,20}.

Odontaster meridionalis color is variable and includes yellow-white, dirty yellow, orange yellow, bright orange,
pale brown, and a grey center grading to white at arm tips [2,7). O. meridionalis is generally pale brown or yellowish
white on the dorsal surface and lighter on the ventral surface {11}.

43

@Peter Brueggeman

Odontaster roseus and Odontaster pearsei have been found in the Antarctic Peninsula and Terra Nova Bay [13.17}.
A classification key for Odontaster species was published in 2010 {13}. Odontaster roseus, O. pearsei, and O.
validus can be differentiated by the number of spines on abactinal plates and their length, and the marginal plates
and spines, in addition to genetic sequences [17}.

44

Odontaster meridionalis is found throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, South
Sandwich Islands, South Georgia Island, Shag Rocks, Straits of Magellan, Tierra del Fuego, Bouvet Island, Marion
and Prince Edward Islands, Kerguelen Islands, Crozet Islands, and Heard Island, from 0 to 647 meters depth
[1,2,5,6,7,8,9,10,12,14,15,16]. Genetic study points to O. meridionalis in Kerguelen Islands and O. pencillatus in South
America being a single species occurring in both regions (21).

45

Odontaster meridionalis has been collected at sizes up to nine centimeters in radius from its center to the tip of an
arm [2]. O. meridionalis has a flattened disc with its arms narrowing down on the latter half of their length [g}.

46

@Norbert Wu

Odontaster meridionalis is an important predator of the sponge Homaxinella balfourensis and also eats rossellid
sponges and the sponges Haliclona scotti, Mycale (Oxymycale) acerata, Polymastia invaginata, Hemigellius
fimbriatus, Isodictya setifera, and Pachychalina pedunculata {3,4. O. meridionalis is preyed upon by the anemone
Urticinopsis antarcticus and the seastar Macroptychaster accrescens {5}.

47

” Photograph: Adam G. Marsh
Af ZZ Copyright: 2007

Female Odontaster meridionalis spawn their eggs by broadcasting them into the water where they develop into
feeding larvae ,1). This differs from the more common tendency of McMurdo Sound seastars to have pelagic (open
ocean) non-feeding larval development [1).

48

@Shawn Harper

References: 1: Marine Biology 104:41-46, 1990; 2: The Fauna of the Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial
Research Bulletin 151, New Zealand Oceanographic Institute Memoir 21, 1963; 3: Science 245:1484-1486, 1989; 4: Ecological Monographs 44(1):105-128, 1974 (P.
Dayton, personal communication, 2015: Haliclona dancoi observations are corrected to H. scotti; Gellius tenella corrected to Hemigellius fimbriatus; Rossella racovitzae
observations are corrected to R. podagrosa); 5: Adaptations within Antarctic Ecosystems : Proceedings of the Third SCAR Symposium on Antarctic Biology. George A.
Llano, ed. Washington: Smithsonian Institution; Houston, Tex. : distributed by Gulf Pub. Co., 1977. pp.293-326; 6: AM Clark. B.A.N.Z. Antarctic Research Expedition
1929-1931. Reports, Series B (Zoology and Botany) Volume 9, Asteroidea. Adelaide: BANZAR Expedition Committee, 1962; 7: Discovery Reports 20:69-306 and plates,
1940; 8: Equinodermos Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la Peninsula Antartica. I Bernasconi. Revista del Museo Argentino de Ciencias
Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Zoologia (aka Ciencias Zoologicas) 9(10):211-281 and plates, 1970; 9:
South African Journal of Antarctic Research 23(1-2):37- 70, 1993; 10: Scientia Marina 63(Supplement 1):433-438, 1999; 11: John Dearborn, personal communication, 2001;
12: Revista Ciencia y Tecnologia del Mar 29(1):91-102, 2006; 13: Integrative and Comparative Biology 50(6):981-992, 2010; 14: Polar Biology 38:799-813, 2015; 15: Polar
Biology 41:2423-2433, 2018; 16: Amazing Antarctic asteroids: a guide to the starfish of the Ross Sea. Kate Neill et al. NIWA, New Zealand, Version 1, 2016
www.niwa.co.nz/coasts-and-oceans/marine-identification-guides-and-fact-sheets/amazing-antarctic-asteroids 17: Diversity 14:457, 2022. doi.org/10.3390/d14060457; 18:
The Fauna of the Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial Research Bulletin 151, New Zealand Oceanographic
Institute Memoir 21, 1963; 19: Discovery Reports 20:69-306 and plates, 1940; 20: Equinodermos Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la
Peninsula Antartica. I Bernasconi. Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias
Naturales. Zoologia (aka Ciencias Zoologicas) 9(10):211-281 and plates, 1970; 21: Diversity 15:1129, 2023. doi.org/10.3390/d15111129

49

seastar Odontaster validus

4 > oy re . 1 IR
UTA Bo” houa de> SS Ap boii *

RIA wR SNA

Zw, ipa be oa i OR HK Aa igo
( Dene. aa Ain AATE™ y)

Odontaster validus is found throughout Antarctica & the Antarctic Peninsula, South Shetland Islands, South
ae Islands, South Sandwich Islands, South eee Island, Shag Rocks, Chile, Falkland Islands, Bouvet

Reported distribution beyond Antarctica is not supported by mitochondrial DNA data, which shows Odontaster
validus to be geographically isolated to Antarctic and subantarctic waters [21).

@Shawn Harper

.

Odontaster validus has a broad disc and short arms tapering to blunt tips ,7}. O. validus varies in color including
dark brown, purple, purple-red, orange, orange-yellow, red-orange, red, brick red, dark carmine, and pink; it may
have light colored arm tips [7,11,14,22}. Odontaster validus is usually bright to dull red on the dorsal (abactinal)
surface, and yellowish white to pale pink on the ventral (actinal) surface [16]. However O. validus can be orange-
yellow colored on its dorsal surface in addition to its characteristic dark pink/red color, thus confounding visual
identification by color for this species [22]. Odontaster validus, O. roseus, and O. pearsei can be differentiated by
the number of spines on abactinal plates and their length, and the marginal plates and spines, in addition to genetic
sequences |2).

eH

Odontaster validus has been collected at sizes up to seven centimeters in radius from center to arm tip 17,11). O.
validus has a characteristic position with its arm tips slightly raised ,7}.

52

Here's a juvenile and adult of Odontaster validus.

Size-frequency distribution of Odontaster validus can vary with location and is a reflection of the general level of
productivity of a habitat: at McMurdo Station, their size and number decrease with depth; at Cape Evans, they are
more numerous and generally smaller; and, at East Cape Armitage, they are less numerous and very small 13}.

Odontaster validus is slow growing; well-fed individuals need about nine years to reach thirty grams wet weight
which is near the mean size of shallow-water individuals at McMurdo Station [3]. Based on its growth rate, collected
sizes, and knowledge from other seastars, O. validus may live beyond one hundred years of age, with very low
turnover in a population 117).

53

CtNorbere’. Wu

Here Odontaster validus is ganging up and eating the sea urchin Sterechinus neumayeri; little red amphipods are
stealing food in the process. O. validus appears voracious, being very numerous in some areas and piled up in
feeding groups; one study found that almost 50% of O. validus in the study area were engaged in feeding with their
everted stomach 113}.

Odontaster validus is omnivorous, capable of filter-feeding and eating a varied diet: detritus, small crustaceans
including amphipods and the isopod Glyptonotus antarcticus, seastars, molluscs (scallop Adamussium colbecki,
gastropods, bivalves Laternula elliptica and Limatula hodgsoni), hydroids (including Hydrodendron arboreum), bryozoans, sponges
(rossellid sponges, Homaxinella balfourensis, Scolymastra joubini, Tetilla leptoderma), ostracods, sea urchin Sterechinus
neumayeri, polychaete worms, carrion (including dead Weddell seals), feces (from Weddell seals), diatoms, and algae
[5,8,9,13,15]. O. validus has been observed feeding on the detrital film on the surface of the sponge Cinachyra
antarctica [13].

54

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ao)
uy
iy)
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=

56

at

Odontaster validus seastars piled up and feeding on Weddell seal feces under ice holes used by Weddell seals to
enter and exit the water through the thick sea ice.

58

Odontaster validus is a prey item of the seastar Macroptychaster accrescens |;,and of the anemone Urticinopsis
antarcticus {6}.

Odontaster validus broadcast-spawns larvae which feed on bacteria and algae and have a low metabolic rate (which
predicts long-term larval survival); larvae of a comparable temperate seastar eat only algae and have a higher
metabolic rate /1,2}.

39

@Norbert Wu

Here’s a gang attack on Acodontaster sp. seastar. A single Odontaster validus climbs up onto a ray of the seastar,
everts its stomach, and digests a hole into it. An attack by a single O. validus isn't fatal but nearby O. validus
probably respond to the release of coelomic fluid from the seastar and join the attack [5}.

The seastars Odontaster validus and Acodontaster conspicuus are the two greatest predators on McMurdo sponges
[5]: Odontaster validus is a foundation species in the McMurdo sponge-dominated benthic ecosystem and is the
keystone to the interaction between the rossellid sponges and one of their primary predators, the large Antarctic
seastar Acodontaster conspicuus {4}. A. conspicuus would reach population densities destroying the sponge
community if not kept in check by O. validus which preys upon its larvae, young and adults [5}.

60

@QNorbert. Wu

Showing an Acodontaster sp. seastar here, eventually the larger seastar's movement is slowed, and more Odontaster
validus seastars attack. Seastars can become completely buried under high piles of attacking Odontaster validus
seastars and Parborlasia corrugatus worms [5].

61

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=
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Odontaster validus seastars attack an urchin.

62

@Adam:.:;Marsh

Odontaster validus seastar eating a gorgonian.

Odontaster validus is the most abundant seastar in the shallow shelf waters of Antarctica and is most abundant from
15 to 200 meters {9}.

TAXONOMIC NOTE: A classification key for Odontaster species was published in 2010 {13}. Three closely
related species in Odontaster have been identified by molecular barcoding (O. validus, O. roseus, and O. pearsei),
but morphological variation in a single population of Odontaster validus from one locality covers the whole range
of that reported for O. roseus, and overlaps that of O. pearsei [18,1921]. Odontaster roseus, O. pearsei, and O. validus
can be differentiated by the number of spines on abactinal plates and their length, and the marginal plates and
spines, in addition to genetic sequences |23).

63

Photograph: Adam.G. Marsh
Copyright: 2007

References: 1: Antarctic Journal of the United States 26(5):170-172, 1991; 2: Antarctic Journal of the United States 26(5):163-165, 1991; 3: Marine Biology 99(2):235-246,
1988; 4: Colloquium on Conservation Problems in Antarctica, Sept. 10-12, 1971, Blacksburg, VA, Proceedings. BC Parker, ed. Lawrence, Kansas, Allen Press, 1972. pp.81-
96; 5: Ecological Monographs 44(1):105-128, 1974 (Paul Dayton, personal communication, 2015: Rossella racovitzae observations are corrected to R. podagrosa); 6:
Antarctic Ecology, Volume 1. MW Holdgate, ed. NY: Academic Press, 1970. pp244- 258; 7: The Fauna of the Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand
Department of Scientific and Industrial Research Bulletin 151, New Zealand Oceanographic Institute Memoir 21, 1963; 8: Science 245:1484- 1486, 1989; 9: Adaptations
within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. GA Llano, ed. Washington: Smithsonian Institution; Houston, Tex.:
distributed by Gulf Pub. Co., 1977. pp.293-326; 10: AM Clark. BANZ Antarctic Research Expedition 1929-1931. Reports, Series B (Zoology and Botany) Volume 9,
Asteroidea. Adelaide: BANZAR Expedition Committee, 1962; 11: Discovery Reports 20:69-306 and plates, 1940; 12: South African Journal of Antarctic Research 23(1-
2):37-70, 1993; 13: New Zealand Antarctic Record 9(2):34-52, 1989; 14: Equinodermos Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la Peninsula
Antartica. I Bernasconi. Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales.
Zoologia (aka Ciencias Zoologicas) 9(10):211-281 and plates, 1970; 15: Antarctic Science 12(1):64-68, 2000; 16: John Dearborn, personal communication, 2001; 17:
Australian Natural History 16(7):234-238, 1969; 18: Integrative and Comparative Biology 50(6):981-992, 2010; 19: Polar Biology 41:2159-2165, 2018; 20: Amazing
Antarctic asteroids: a guide to the starfish of the Ross Sea. Kate Neill et al. NIWA, New Zealand, Version 1, 2016 www.niwa.co.nz/coasts-and-oceans/marine-identification-
guides-and-fact-sheets/amazing-antarctic-asteroids; 21: Polar Biology 34(4):575—586, 2011; 22: Diversity 14:457, 2022. doi.org/10.3390/d14060457

64

seastar Perknaster aurorae

Perknaster aurorae is found in the Antarctic
Peninsula, South Shetland Islands, South
Sandwich Islands, South Georgia Island, and
Shag Rocks, and probably throughout
Antarctica, from 18 to 310 meters depth 11,4,5).
P. aurorae has a large convex disc and long
arms that are wide at the base [1). P. aurorae
has been collected at sizes up to fourteen
centimeters in radius from its center to the tip
of an arm [1,3]. The dorsal color of P. aurorae
ranges from brick with dark red markings to
beige with brick bands along the arms and on
the disc; the ventral color is pale yellow, with
dark red interradial bands that reach the oral
region [1,2].

References: 1: Equinodermos Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la Peninsula Antartica. I Bernasconi.
Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias
Naturales. Zoologia (aka Ciencias Zoologicas) 9(10):211-281 and plates, 1970; 2: Isidro Bosch, personal communication, 1999; 3: AM
Clark. B.A.N.Z. Antarctic Research Expedition 1929-1931. Reports, Series B (Zoology and Botany) Volume 9, Asteroidea. Adelaide:
BANZAR Expedition Committee, 1962; 4: Discovery Reports 20:69-306 and plates, 1940; 5: Tethys 6(3):63 1-653, 1974

65

seastar Perknaster fuscus

_

Perknaster fuscus is found throughout Antarctica south of sixty degrees, in depths of 0 to 457 meters /5,3}.

The color of Perknaster fuscus ranges from shades of red with darker spots or stripes to a yellow or light orange
background with red markings |7).

Perknaster fuscus has a color morph at Turtle Rock due to its diet of urchins and Odontaster validus seastars {6}.

66

Perknaster fuscus has been collected at sizes up to fourteen centimeters in radius from its center to the tip of an arm
[7]

67

GAdam G Marsh

A small Perknaster fuscus is shown here,
with a radius of four centimeters [10].

68

S
C
®
=
S
=
©

69

@Henry Kaiser / NSF

70

71

Juvenile Perknaster fuscus are important predators of the sponge Homaxinella balfourensis (shown here) and also eat
the sponges Tetilla leptoderma, Haliclona scotti, Mycale (Oxymycale) acerata, Polymastia invaginata, and
Kirkpatrickia variolosa {1,2}.

@Nerbert

Here the sea urchin Sterechinus neumayeri is crawling across an adult Perknaster fuscus. Adult Perknaster fuscus
are food-specific predators of the sponges Tetilla leptoderma, Anoxycalyx (Scolymastra) joubini, and Mycale
(Oxymycale) acerata {2,3}.

pee

A juvenile Perknaster fuscus is below three Odontaster validus seastars, all eating the bush sponge Homaxinella
balfourensis.

‘S

a

~*~

y

@Norbert Wu

Perknaster fuscus can be an opportunistic scavenger on dead material [5]. Here P. fuscus is scavenging on
something with the proboscis worm Parborlasia corrugatus.

a

A juvenile Perknaster fuscus eating the bush sponge Homaxinella balfourensis.

Perknaster fuscus is eaten by the anemone Urticinopsis antarcticus 4). P. fuscus appears to be chemically defended
from most predators |9}.

7

About the Perknaster seastar in the above photo, Paul Dayton said “I mentioned a white (Perknaster) eating O.
validus (seastar) and urchins at Turtle Rock and points north ... I transplanted them to see if they would switch prey.
Here is a photo ...that is proof that the white with pink patches did switch and eat Mycale...." (12).

78

@Shawn: Aer per

TAXONOMIC NOTE: World Register of Marine Species lists a Perknaster fuscus antarcticus subspecies as an
alternate representation (an accepted name though slightly less preferred) of Perknaster fuscus, stating “maintained
as subspecies of Perknaster fuscus Sladen, 1889 by Bernasconi (1967) without reference to A.M. Clark (1962)” [11).

79

References: 1: Science 245:1484-1486, 1989; 2: Ecological Monographs 44(1):105-128, 1974 (P. Dayton, personal communication, 2015: Haliclona dancoi observations are
corrected to H. scotti); 3: Biologie des Spongiaires, Sponge Biology. C Levi and N Boury-Esnault, eds. Colloques Internationaux du Centre National de la Recherche
Scientifique Number 291. Paris: Centre National de la Recherche Scientifique, 1979. pp.271-282; 4: Antarctic Ecology, Volume 1. MW Holdgate, ed. NY: Academic Press,
1970. pp244-258; 5: Adaptations within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A. Llano, ed. Washington:
Smithsonian Institution; Houston, Tex.: distributed by Gulf Pub. Co., 1977. pp.293-326; 6: P Dayton, personal communication, 1998; 7: The Fauna of the Ross Sea, Part 3,
Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial Research Bulletin 151, New Zealand Oceanographic Institute Memoir 21, 1963; 8: Tethys
6(3):63 1-653, 1974; 9: Antarctic Ecosystems: Models for Wider Ecological Understanding. W Davison, C Howard-Williams, P Broady, eds. Christchurch, NZ: New Zealand
Natural Sciences, 2000. pp. 158-164; 10: Paul Cziko, personal communication, 2004; 11: Mah, C.L. (2023). World Asteroidea Database. Perknaster fuscus antarcticus
(Koehler, 1906). Accessed through: World Register of Marine Species at: www.marinespecies.org/aphia.php?p=taxdetails&id=172754 on 2023-10-27; 12: Paul Dayton,
personal communication, 2023

seastar Glabraster antarctica

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Glabraster antarctica is found in Antarctica and South Shetland Islands, South Sandwich Islands, South Georgia
Island, Shag Rocks, Bouvet Island, Burdwood Bank, Falkland Islands, Chile, Uruguay, Argentina, Crozet Islands,
Kerguelen Islands, Marion and Prince Edward Islands, Marquarie Island, and Heard Island, from 0 to 3,200 meters
depth [3,4,6,8,9,10,13,14,15,16,17,19]. .

Glabraster antarctica has been collected at sizes up to 9.7 centimeters in radius from its center to the tip of an arm
[5,9,14].

81

Ciewoaee- Rogelh:

Glabraster antarctica varies in coloration as shown here. The color of G. antarctica can include off white, deep
scarlet, pink, red purple, brick red, reddish orange, dark orange, bluish white, purplish white, bluish-grey, yellowish
white, grey, pale orange, pale red and has also been described as various tints of dark red [6,8,9,10,13,15).

82

Pe
:
ie
i
S
ee
es
het
es
es

Glabraster antarctica is a ciliary-mucous feeder consuming the small organisms, diatoms, and detritus that shower
down on its back by passing them along to its mouth 11,2). Glabraster antarctica occasionally is an active predator
on larger prey and is a scavenger [2].

84

Glabraster antarctica is a morphologically variable species with morphotypes that are not genetically distinct [1).
The Antarctic Peninsula morphotype is small, with strong abactinal spination, while the large Scotia Arc
morphotype lacks abactinal spines [13]. The Magellanic morphotype is bright red-orange with distinct abactinal
spination [18).

iPe

au mn

e % Here is a spiny form of Glabraster

“~ oe antarctica {7,10|. Adult Glabraster
antarctica have well developed dorsal
spines or tubercles {1,2,4,9,10]. However
this distinction is not so distinct in
some specimens {4,6}.

Taxonomic Note: Porania antarctica assigned to Glabraster genus, and subspecies glabra was synonymized {11,13}.

References: 1: The Fauna of the Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial Research Bulletin 151, New Zealand
Oceanographic Institute Memoir 21, 1963; 2: Adaptations within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A. Llano,
ed. Washington: Smithsonian Institution; Houston, Tex. : distributed by Gulf Pub. Co., 1977. pp.293-326; 3: Los Equinodermos Colectados por el "Walther Herwig" en el
Atlantico Sudoeste. I Bernasconi. Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias
Naturales. Hidrobiologia 3(3):287-334 and plates, 1973; 4: AM Clark. B.A.N.Z. Antarctic Research Expedition 1929-1931. Reports, Series B (Zoology and Botany) Volume
9, Asteroidea. Adelaide: BANZAR Expedition Committee, 1962; 5: Biological Bulletin 177(1):77-82, 1989; 6: Discovery Reports 20:69-306 and plates, 1940; 7: Isidro
Bosch, personal communication, 1999; 8: South African Journal of Antarctic Research 23(1-2):37-70, 1993; 9: Asteroidea with a Survey of the Asteroidea of the Chilean
Shelf. FJ Madsen. Lunds Universitets Arsskrift. Ny Foljd, Avd. 2. Bd 52. Nr 2. Kungliga Fysiografiska Sallskapet Handlingar. Ny Foljd, Bd 67, Nr 2. Reports of the Lund
University Chile Expedition 1948-49. Number 24. Lund: CWK Gleerup, 1956; 10: Memoirs of Museum Victoria 57(2):167-223, 1998; 11: AM Clark & ME Downey.
Starfishes of the Atlantic. Chapman & Hall Identification Guides, 3. London: Chapman & Hall 1992; 12: W. Percy Sladen. Zoology Part 51. Report on the Asteroidea
(Starfish) collected by H.M.S. Challenger during the years 1873-1876. Report on the Scientific Results of the Voyage of HMS Challenger during the Years 1873-76.
Zoology, Vol 30, Text. London, HMSO: 1889. pp 360-362; 13: Zootaxa 3795(3): 327-372, 2014; 14: Fauna der Antarktis. J Sieg & JW Wagele, eds. Berlin: P Parey, 1990;
15: Equinodermos Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la Peninsula Antartica. I Bernasconi. Revista del Museo Argentino de Ciencias
Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Zoologia (aka Ciencias Zoologicas) 9(10):211-281 and plates, 1970; 16:
Polar Biology 41:2423-2433, 2018; 17: Amazing Antarctic asteroids: a guide to the starfish of the Ross Sea. Kate Neill et al. NIWA, New Zealand, Version 1, 2016
www.niwa.co.nz/coasts-and-oceans/marine-identification-guides-and-fact-sheets/amazing-antarctic-asteroids; 18: Ecology and Evolution 8(21):10621-10633, 2018; 19:
Frontiers in Ecology and Evolution 12:1455329, 2024. doi: 10.3389/fevo.2024.1455329

85

seastar Psilaster charcoti

© Jim Mastro

Psilaster charcoti is found throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, South Orkney Islands, South
Sandwich Islands, South Georgia Island, Bouvet Island, Crozet Islands, Macquarie Island, Argentina, and Chile, from 10 to 3,900 meters
depth [1,3,4,5,6,7). The dorsal surface of P. charcoti is slightly convex; its arms are wide at the base, have steeply vertical sides, and taper
evenly from its broad disc to the sharp arm tips [1,4). P. charcoti has a central anus, long slender tube feet without distinct sucking discs,
and its oval madreporite is between arms and nearer the edge than center /1;. The lack of distinct suckers on the tube feet of P. charcoti
indicates a preference for a muddy environment ,1). P. charcoti has been collected at sizes up to sixteen centimeters in radius from its
center to the tip of an arm (2,4). The color of P. charcoti is reddish brown, brown-yellow, light tan, bright or pale pink, purplish, or violet
and its edges may be lighter; young may be pale yellow {1,4,6). Psilaster charcoti has been collected with its stomach filled with mud, fecal
material, the remains of a polychaete worm, and pieces of a colonial ascidian; it has also been captured with hooks baited with fish chunks
3). Thus P. charcoti is an active predator on some invertebrates and ingests mud to eat organisms therein; it also scavenges on feces and
dead organisms ,3}. P. charcoti is noted as being slimy, suggesting ciliary-mucus feeding ;3}.

References: 1: The Fauna of the Ross Sea, Part 3, Asteroidea. HES Clark. New Zealand Department of Scientific and Industrial Research Bulletin 151, New Zealand
Oceanographic Institute Memoir 21, 1963; 2: Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Biologie 63:175-184, 1993; 3: Adaptations within Antarctic
Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A. Llano, ed. Washington: Smithsonian Institution; Houston, Tex.: distributed by
Gulf Pub. Co., 1977. pp.293-326; 4: Equinodermos Antarticos. II. Asteroideos. 5. Asteroideos de la Extremidad Norte de la Peninsula Antartica. I Bernasconi. Revista del
Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Zoologia (aka Ciencias Zoologicas)
9(10):211-281 and plates, 1970; 5: Tethys 6(3):631-653, 1974; 6: Memoirs of Museum Victoria 57(2):167-223, 1998; 7: Amazing Antarctic asteroids: a guide to the starfish
of the Ross Sea. Kate Neill et al. NIWA, New Zealand, Version 1, 2016 www.niwa.co.nz/coasts-and-oceans/marine-identification-guides-and-fact-sheets/amazing-antarctic-
asteroids

86

© Rob Robbins

possibly the seastar
Pteraster affinis

This seastar was photographed at New
Harbor at about twelve meters depth (2).

Taxonomic Note: Pteraster affinis reported by AM Clark 1). John Pearse said this photo looked like the aculeatus
subspecies 3). That subspecies has been synonymized into the affinis parent species [4]. Genetic analysis suggests
that Pteraster affinis should have several species [5]. An identification key to the Southern Ocean Pterasteridae is at
pterasteridae-so.identificationkey.org/mkey.html [accessed 10 November 2021].

References: 1: AM Clark. B.A.N.Z. Antarctic Research Expedition 1929-1931. Reports, Series B (Zoology and Botany) Volume 9,
Asteroidea. Adelaide: BANZAR Expedition Committee, 1962; 2: Rob Robbins, personal communication, 2000; 3: John Pearse, personal
communication, 2000; 4: Mah, C. (2014). Pteraster affinis Smith, 1876. In: Mah, C.L. (2014) World Asteroidea database. Accessed
through: World Register of Marine Species at www.marinespecies.org/aphia.php?p=taxdetails&id=172780 on 2014-09-03; 5: Zoological
Journal of the Linnean Society 192(1):105-116, 2021

87

heart urchin Abatus sp.

@). Da ay

_

-,

Species of Abatus urchins reported in the
McMurdo Sound area are ingens, nimrodi,
and shackletoni [15]. Species of Abatus
urchins reported in Terra Nova Bay of the
Ross Sea are ingens, nimrodi, shackletoni,
_ agassizii, cavernosus, cordatus, curvidens,
and elongatus [16].

Urchins of the genus Abatus are
characterized by what's called a
peripetalous fasciole in adult urchin tests
(shells); this is a different-looking band of
fine densely-packed spines circum-

4, navigating the top of the test (see it below
this red line) 115).

88

A live Abatus urchin showing its peripetalous fasciole, a band of fine densely-packed spines circum-navigating the
top.

ae tin ae ae

Heart urchins are deposit feeders, using their oral tube feet to gather up detritus (13). Heart urchins have a dense coat
of spines which keeps sediment away from the urchin's surface, thus maintaining a water-filled surrounding space
that the urchin uses for respiration while buried [13}.

90

An Abatus sp. urchin.

An Abatus sp. urchin.

m4

+

Me

91

Abatus shackletoni is found throughout Antarctica and the Antarctic Peninsula from 8 to 631 meters depth
[1,2,3,4,9,10,12,14,15]. Near Cape Evans, Abatus shackletoni occurs in loose gravel and cobble habitats [1). At Rocher
Jacobsen in the Pointe Géologie Archipelago of Terre Adélie, Abatus shackletoni individuals live completely buried
in the silty sediment [14]. The shell (test) length of Abatus shackletoni can be up to 6.7 centimeters in length, with a
typical size being four centimeters [6,11,15]. The test of Abatus shackletoni is more or less ovoid, about as long as it is
broad, has a regular peripetalous fasciole, and may or may not have a faint notch at the anterior end [4,5,9,10,15). The
color of Abatus shackletoni is brown to grayish-purple (15).

Abatus (Pseudabatus) nimrodi is found in eastern Antarctica from 2 to 716 meters depth [1,4,5,6,9,14]. Abatus
(Pseudabatus) nimrodi can be found partly or completely burrowed into muddy or silty sediment [7,14]. Abatus
(Pseudabatus) nimrodi is common along the western oligotrophic side of McMurdo Sound including New Harbor;
it can be found buried just below the surface of fine, silty sediment at New Harbor [1,6.9). The shell (test) length of
Abatus (Pseudabatus) nimrodi can be up to six centimeters with an average size of 3 - 4 centimeters [15]. The brood
pouches of Abatus (Pseudabatus) nimrodi are widely separated from the apical system at the top of the test (shell)
(15]. The color of Abatus (Pseudabatus) nimrodi is dark brown to nearly black (4,15).

Abatus ingens has been found along the Antarctic coast from 20 to 761 meters depth, and is very large, up to six to
seven centimeters in length (15). Abatus ingens has a triangular-looking ambitus at its posterior end, has a sinuous-
looking peripetalous fasciole, and is very dark, almost black, including its spines (15).

Here's a look at the four brood pouches on
an Abatus test (shell).

Abatus shackletoni broods an average of 22
yolk-feeding embryos and juveniles in each
of four depressed elongated brood pouches
on the urchin's dorsal (aboral) surface;
Abatus (Pseudabatus) nimrodi broods an
average of eighteen [1,6}.

92

Here, Abatus embryos and juveniles are
pulled out of their brood pouches for
illustration. Development of embryos
within the brood pouch takes at least
eight months |). Eggs are released into
the brood pouches and fertilized there

» throughout most or all of the year {6).
From August to January, 71-100% of
Abatus shackletoni females are brooding
embryos {6}. From November to January,
60-84% of Abatus (Pseudabatus)
nimrodi females are brooding embryos

[6].

Two types of spines form a protective
arch over the Abatus brood pouch 11,6}.

stages of development in the brood
] pouch and are larger in size relative to
» the juveniles of Abatus shackletoni (1,6}.

93

The production of large,

| robust Abatus (Pseudabatus)
nimrodi juveniles may
increase their survival for
escaping the predatory brittle
stars which occur in their
environment; these brittle
stars are not abundant where
Abatus shackletoni is found

[6].

The diversity of Antarctic sea urchins with its prevalence of brooding (thirty-nine of sixty Antarctic and
subantarctic species -- 65%) may be a process of species-level selection via extinction and speciation rates related
to pelagic or protected development of their young [7,8).

Taxonomic Note: Genetic analysis showed Abatus koehleri to be A. shackletoni {16}.
Abatus ingens, nimrodi, shackletoni, agassizii, cavernosus, cordatus, curvidens, and elongatus were reverse
described after genetic analyses [16}.

References: 1: Journal of Morphology 216(1):79-93, 1993; 2: Symposium on Antarctic Oceanography. Santiago, Chile 13-16 September 1966. Published by Scott Polar
Research Institute for Scientific Committee on Antarctic Research. Cambridge, Printed by W. Heffer, 1966. p.162; 3: R Koehler. Echinodermata Echinoidea. Australasian
Antarctic Expedition 1911-1914. Scientific Reports. Series C, Zoology and Botany. Vol 8 Part 3. Sydney: David Harold Paisley, Government Printer, 1926; 4: A Monograph
of the Echinoidea. Volume 2, Spatangoida. 2. Amphisternata. 2. Spatangidae, Loveniidae, Pericosmidae, Schizasteridae, Brissidae. T Mortensen. Copenhagen: CA Reitzel,
1951. pp.249-263; 5: Hawaiian and Other Pacific Echini. The Spatangina. HL Clark. Memoirs of the Museum of Comparative Zoology at Harvard College. Volume 46
Number 2. Cambridge: Museum of Comparative Zoology at Harvard College, 1917. pp. 174-177; 6: Invertebrate Reproduction and Development 17(3):181-191, 1990; 7:
Vie et Milieu 47(4):38 1-387, 1997; 8: Evolution 50(2):820-830, 1996; 9: Echinoderms Through Time: Proceedings of the Eighth International Echinoderm Conference,
Dijon, France, 6-10 September 1993. B David et al, eds. Rotterdam; Brookfield, Vt.: Balkema, 1994. pp.749-756; 10: Equinodermos Antarticos. I. Equinoideos. 1.
Equinoideos de Shetland del Sur y Archipielago Melchior. I Bernasconi. Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de
Investigacion de las Ciencias Naturales. Zoologia 9(9):197-210 and plates, 1969; 11: Biogeografia de la Peninsula Antartica, Archipielagos y Mares Adyacentes. N Bellisio
& A Tomo. Buenos Aires: Servicio de Hidrografia Naval, 1974; 12: A Survey of the Marine Fauna in Shallow Coastal Waters of the Vestfold Hills and Rauer Islands,
Antarctica. MJ Tucker & HR Burton. ANARE Research Notes 55, 1987; 13: www.nhm.ac.uk/palaeontology/echinoids/; 14: Polar Biology 27(3):177-182, 2004; 15:
Antarctic Echinoidea. B David, T Chone, R Mooi & C De Ridder. Ruggell, Liechtenstein: ARG Gantner, 2005; 16: Diversity 15: 875, 2023 doi.org/10.3390/d15070875

94

pencil urchin Ctenocidaris perrieri

Ctenocidaris perrieri is found in Antarctica and the Antarctic Peninsula, Kerguelen Island, Crozet Island, and
Heard Island from 6 to 602 meters depth [1,2,5,6,7).

95

The test (shell) of Ctenocidaris perrieri has been measured at sizes up to 6.7 centimeters and is purple or purple-
brown in color [7,8,9}.

Ctenocidaris perrieri has long, slender, coarsely thorny primary spines measured at lengths up to 8.5 centimeters
and covered with a thick, spongy coat of hairs |2}. The primary spines of C. perrieri are typically twice as long as
the horizontal diameter of the test (shell) 2}.

Eleven sponge species were found to grow on the spines of Ctenocidaris perrieri, with the most common being
Homaxinella balfourensis, Isodictya erinacea, Iophon unicorne, and Haliclona (Rhizoniera) dancoi; the urchins
increase the dispersal of the sponges by being “islands” of suitable habitat ,10).

©Shawn, Sessa

AV j

. \ e “5 \%

Ctenocidaris perrieri broods its embryos and juveniles in the region surrounding its mouth (the peristome) [3,3).

98

©Shawn Harper

The diversity of Antarctic sea urchins with its prevalence of brooding (thirty-nine of sixty Antarctic and subantarctic species
-- 65%) may be a process of species-level selection via extinction and speciation rates related to pelagic or protected
development of their young ;3,4}.

References: 1: Bulletin du Museum National d'Histoire Naturelle, Section A, Zoologie, Biologie, et Ecologie Animales 14(2):405-441, 1992; 2: A Monograph of the
Echinoidea. Volume 1, Cidaroidea. T Mortensen. Copenhagen: CA Reitzel, 1928. pp123-124; 3: Evolution 50(2):820-830, 1996; 4: Vie et Milieu 47(4):381-387, 1997; 5:
NZOI Records (New Zealand Oceanographic Institute) 3(1):1-6, 1976; 6: Jim Mastro, personal communication, 1999 [6 meters at Explorer's Cove in New Harbor]; 7:
Equinodermos Antarticos. I. Equinoideos. 1. Equinoideos de Shetland del Sur y Archipielago Melchior. I Bernasconi. Revista del Museo Argentino de Ciencias Naturales
"Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Zoologia 9(9):197-210 and plates, 1969; 8: T Mortensen. B.A.N.Z. Antarctic
Research Expedition 1929-1931. Reports, Series B (Zoology and Botany) Volume 4, Part 10 Echinoidea. pp. 287-310 plus plates. Adelaide: BANZAR Expedition
Committee, 1950; 9: Echinodermes (Asteries, Ophiures et Echinides). R Koehler. Deuxieme Expedition Antarctique Francaise (1908-1910) commandee par le Dr Jean
Charcot. Sciences Naturelles. Documents Scientifiques. Paris: Masson et Cie, 1912; 10: Polar Biology 32(7):1067-1076, 2009

99

sea urchin Sterechinus neumayeri

Sterechinus neumayeri is found in Antarctica and the Antarctic Peninsula, South Shetland Islands, South Orkney
Islands, South Sandwich Islands, South Georgia Island, South Patagonia Island, Prince Edward Island, Marion
Island, Crozet Island, and Kerguelen Island at depths from 5 to 640 meters [s,9,10).

Sterechinus neumayeri is abundant in shallow waters of McMurdo Sound at depths less than fifteen meters and
plays a major role in McMurdo Sound's benthic ecosystem.

101

102

O©Norbert Wu

The color of the test (shell) and spines of Sterechinus neumayeri is variable, from greenish- olive to dark
purplish/violet or whitish; the test is more generally greenish-olive or green-gray [8,9,10]. It is slow growing, reaching
a maximum diameter of seven centimeters at forty years of age [1).

The bare test (shell) of the genus Sterechinus is distinguished by a large periproct within its ring of apical plates,
distinctly darker lines formed by tube feet in the pore zones, and denser distribution of tubercules on the oral side
than the aboral side 119]

103

ONS ge Shaaw

Largely herbivorous, half of the diet of Sterechinus neumayeri is algae; it also eats diatoms, foraminiferans,
sponges, bryozoans, hydrozoans, polychaetes including Spirorbis sp., and amphipods (4,18,20}.

104

©Nerbert Wu

Above, Sterechinus neumayeri and the seastar Odontaster validus cruise the shallow bottom foraging for food
around the crystalline anchor ice.

105

Weddell seal feces are a food item for Sterechinus neumayeri in shallow water, which can be observed piled up on
feces along with the seastar Odontaster validus. The gut content of S. neumayeri is filled with seal feces at locations
where this occurs {5}.

Sterechinus neumayeri has been observed feeding on the detrital film on the surface of the sponge Cinachyra
antarctica [13].

Like many other urchins,
Sterechinus neumayeri attaches bits
of shell and debris to itself. The
shells and debris often have stinging
hydroids on them (see the whitish
polyps on top left of the urchin). If an
anemone like Urticinopsis
antarcticus touches the urchin's
hydroids, it releases the urchin. If
the urchin is aware of the anemone's
tentacles, the urchin releases its
protective camouflage and escapes
the anemone's grasp. If this
camouflage isn't present on the
urchin, the anemone captures and
eats the urchin (3).

Predators of the urchin Sterechinus neumayeri include the anemones Urticinopsis antarcticus and Isotealia
antarctica, the octopus Pareledone sp., the fish Trematomus bernacchii, the seastars Macroptychaster accrescens
and Odontaster validus [shown here], and the brittle star Ophiosparte gigas [6,7,11,12,14,16].

108

Sterechinus neumayeri attaches pieces of
algae like Phyllophora antarctica and Iridaea
cordata to itself as protection against the
anemone /sotealia antarctica (14).

Both algae manufacture unpalatable defensive
chemicals to avoid getting eaten by
Sterechinus. neumayeri, yet the urchin
attaches algal pieces to itself as a detachable
shield to shed when the anemone's tentacles
grab onto the attached algae (14,15).

The Antarctic scallop Adamussium colbecki may be colonized on either shell by small hydroids Hydractinia
angusta 7. H. angusta hydroids eat tube feet and pedicellariae of sea urchins including Sterechinus neumayeri,
which graze on the algal film growing on the surface of the scallop's shell but is not a predator of the scallop in.
Adamussium colbecki shells are very thin, and such urchin grazing may damage the shell; thus the hydroids act in
defense of the scallop 11.

110

At some sites where these algae occur with Sterechinus neumayeri, 96.5% of the urchins were using Phyllophora
antarctica for 90% or more of their cover [14). This is a mutually beneficial relationship between S. neumayeri and
the algae 14}. The urchins move fertile drift algae throughout sunlit waters, thereby keeping drift algae in the
reproductive area with other attached and drift algae; the urchins also extend the vertical and horizontal range of the
algae and facilitate recolonization after ice scouring of the bottom or when conditions allow growth of attached
plants at greater depths (14).

111

and
\

Jr)

‘~

Spawning Sterechinus neumayeri

Sterechinus neumayeri spawning is timed so
that its feeding larvae are in the plankton during
the short summer peak of phytoplankton
abundance [2}.

References: 1: Marine Biology 124(2):279-292, 1995; 2: Biological Bulletin 173(1):126-135, 1987; 3: Antarctic Ecology, Volume 1. MW Holdgate, ed. NY: Academic
Press, 1970. pp.244-258; 4: Antarctic Journal of the United States 11(1):24-26, 1976; 5: Biological Bulletin 130(3):387-401, 1966; 6: Polar Biology 13(5):347-354, 1993; 7:
Ecological Monographs 44(1):105-128, 1974; 8: A Monograph of the Echinoidea. Volume 3, Part 3. Camarodonta 2. Echinidae, Strongylocentrotidae, Parasaleniidae,
Echinometridae. T Mortensen. Copenhagen: CA Reitzel, 1943. pp.106-108; 9: Bulletin du Museum National d'Histoire Naturelle, Section A, Zoologie, Biologie, et Ecologie
Animales 14(2):405-441, 1992; 10: Equinodermos Antarticos. I. Equinoideos. 1. Equinoideos de Shetland del Sur y Archipielago Melchior. I Bernasconi. Revista del Museo
Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Zoologia 9(9):197-210 and plates, 1969; 11:
Bulletin de l'Institut Oceanographique 66(1368), 1966; 12: Adaptations within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. GA
Llano, ed. Washington: Smithsonian Institution; Houston, TX : distributed by Gulf Pub. Co., 1977. pp.293-326; 13: New Zealand Antarctic Record 9(2):34-52, 1989; 14:
Marine Ecology Progress Series 183:105-114, 1999; 15: Journal of Phycology 34(1):53-59, 1998; 16: Polar Biology 16(5):309-320, 1996; 17: Polar Biology 23(7):488-494,
2000; 18: Polar Biology 26(2):99-104, 2003; 19: Sea Urchins, a Guide to Worldwide Shallow Water Species. H Schultz. Hemdingen, Germany: Heinke & Peter Schultz
Partner Scientific Publications, 2006; 20: Nature Scientific Reports 14:12333, 2024 doi.org/10.1038/s41598-024-62644-5

112

brittle star Astrotoma agassizii

Astrotoma agassizii occurs throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, South
Georgia Island, Shag Rocks, Falkland Islands, Burdwood Bank, and southern Chile and Argentina, in depths from
55 to 1,335 meters [1,2,3,4,8,9].

@®Paul>y @ziko

Astrotoma agassizii is creamy white in color (2). The central disk of A. agassizii can reach a diameter of six
centimeters (2,6). From its growth rings, maximum age of A. agassizii is estimated to be 91 years [7}. A. agassizii
bears live young and is hermaphrodite ,3).

114

The unbranched arms of Astrotoma agassizii are
stout, tapering, and flexible, reaching a length of
seventy centimeters [2,6].

Astrotoma agassizii is usually found on sponges
(as shown here on Anoxycalyx (Scolymastra) joubini),
corals, and other organisms on which it can climb
to be more advantageously placed to feed on prey
drifting by [1,2]. The stomach of A. agassizii
contains diatoms, phytoplankton, foraminiferans,
chaetognaths, bryozoans, polychaetes,

holothurians, ascidians, and primarily crustaceans
(including mysids, copepods particularly Euchaeta
antarctica and Calanoides acutus, euphausiids, and

amphipods, ostracods), indicating that it feeds on
plankton, catching them with its flexible long
arms, which are armed with hooks and spines to
increase catch efficiency [1,2,5,6,71. One or two arms
cling to the perch, while the others extend to feed
[6]. The arms of A. agassizii can be looped and twisted, increasing its efficiency at contacting prey [1). Prey caught by
the arm tips of A. agassizii are rolled up into coils and passed to the mouth 11).

Taxonomic Note: Astrotoma agassizii may be a species complex; Clade I is distributed across the Antarctic
continental shelf and South Georgia and is genetically discrete with dispersing pelagic larva {10}. Reproductive
incompatibility in this species complex was not shown in this work: “Speciation involves the evolution of
reproductive incompatibilities between diverging populations, including prezygotic incompatibilities that prevent
the formation of hybrids and postzygotic incompatibilities that render hybrids sterile or inviable [11).” A “periodic-
like morphological and molecular framework” applied to the Cadlina nudibranch genus in the Kuril Islands showed
the term “cryptic species” should be removed from phylogeny and taxonomy, and that different species of this
complex varied in molecular phylogenetic distances and morphological distinctness [1}.

References: 1: Adaptations within Antarctic Ecosystems, Proceedings of the Third SCAR Symposium on Antarctic Biology. GA Llano,
ed. Washington, DC: Smithsonian Institution, 1977. pp.293-326; 2: The Fauna of the Ross Sea, Part 1, Ophiuroidea. HB Fell. New
Zealand Department of Scientific and Industrial Research Bulletin 142, New Zealand Oceanographic Institute Memoir 18, 1961; 3: Physis
25(69):2-5, 1965; 4: US National Museum Polar Invertebrate Catalog at www.nmnh.si.edu/iz/usap/usapdb.html; 5: Journal of Plankton Research
11(6):1315-1320, 1989; 6: Antarctic Research Series 44:1-28, 1986. Biology of the Antarctic Seas, Volume 17. Washington: American
Geophysical Union, 1986; 7: Berichte zur Polarforschung 194, 1996; 8: Boletim do Instituto Oceanografico (Sao Paulo) 32(1):33-54,
1983; 9: Polar Biology 38:799-813, 2015; 10: Heredity 123:622-633, 2019; 11: eLife 7:e35468. doi.org/10.7554/eLife.35468; 12:
Diversity 2024, 16, 220 doi.org/10.3390/d16040220

115

brittle star Ophiacantha antarctica

is,
2h ss |
» < wears

© Norbert Wu o:

Ophiacantha antarctica is found throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, South
Georgia Island, Bouvet Island, and the Antarctic Ocean south of the polar circle in depths from 20 to 3,398 meters
[1,2,4,5,6,7].

116

©Norbert Wu

The color of Ophiacantha antarctica is variable including disc colors of bluish-grey, grey, reddish, and purple and
arm colors of orange, straw, and pinkish [2,3).

117

/

. Fe
4i¢ | [ MP

The pentagonal central disc of Ophiacantha antarctica is up to 1.3 centimeters in diameter with indentations on the
sides between arms [2.4]. The slender, fragile arms of O. antarctica are up to nine centimeters in length [2,4].

118

COnarbert wt

Ophiacantha antarctica is generally found up on the substrate (rocks, sponges, sessile cnidarians, etc.) [1,3].

Ophiacantha antarctica is an active forager and its diet includes diatoms, foraminifera, copepods, and other
microzooplankton [1).

119

Its flexible arms, long erect and thin arm spines, and climbing ability suggests that Ophiacantha Antarctica feeds
by manipulating its arms and arm spines to capture its food on or near the bottom (1).

Ophiacantha antarctica is the most abundant and widely distributed echinoderm in the Ross Sea, playing an
important role in the benthic biological balance (2).

References: 1: Adaptations within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A.
Llano, ed. Washington: Smithsonian Institution; Houston, Tex.: distributed by Gulf Pub. Co., 1977. pp.293-326; 2: The Fauna of the Ross
Sea, Part 1, Ophiuroidea. HB Fell. New Zealand Department of Scientific and Industrial Research Bulletin 142, New Zealand
Oceanographic Institute Memoir 18, 1961; 3: John Dearborn, personal communication, 1999; 4: Equinodermos Antarticos. III.
Ofiuroideos. 1. Ofiuroidoes del Extremo Norte de la Peninsula Antartica. I Bernasconi and MM D'Agostino. Revista del Museo Argentino
de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Hidrobiologia 4(2):81-133
and plates, 1974; 5: Tethys 6(3):63 1-653, 1974; 6: Polar Biology 26(11):691-699, 2003; 7: Polar Biology 38:799-813, 2015

120

brittle star Ophionotus victoriae

Ophionotus victoriae occurs throughout Antarctica and the Antarctic Peninsula, South Shetland Islands, South
Sandwich Islands, South Georgia Island, and Bouvet Island in depths from 5 to 1,266 meters [3,4,5,6).

121

The arms of Ophionotus victoriae are short, flattened, robust, and depressed, taper rapidly, and can reach a length
of nine centimeters (3).

122

CNGmbert Wu

re

Osha aCe

Ophionotus
victoriae
uses its two
leading arms

| ina typical
> brittle star

rowing
fashion as it

* moves on the

seafloor
searching for
food [2}.

*
ys".
<< uhh bite eee

124
The central disk of Ophionotus victoriae is large, flat and circular and can reach a diameter of four centimeters (3).

Ophionotus victoriae 1s variable in color, including brown, red-brown, brick-red, yellowish-pink, bluish grey, grey,
white, brownish- violet with darker patches, grey with radial fawn streaks, and brownish-grey; pinkish-fawn banded
arms have been observed [3,5].

©Shawn Harper

The maximum age of Ophionotus victoriae has been estimated at 22 years [9}.

Ophionotus victoriaeis a broadcast spawner [10].

126

Ophionotus
victoriae is an
opportunistic
predator and also a
scavenger and

' detrital feeder [2]. O.

victoriae has a
varied diet
including seal feces,
diatoms,
foraminiferans,
tunicates/ascidians,
sponges, hydroids,
bryozoans,
polychaetes, bivalve
molluscs,
crustaceans
(euphausiid krill,
copepods, amphipods,
mysids), Sea urchins,
and brittle stars
[1,2,9].

Ophionotus

victoriae is a significant predator of brittle stars including its own species (cannibalism), which mostly involves

adults eating juveniles (2).

Predators of Ophionotus victoriae include fish and the larger brittle star Ophiosparte gigas (2,71. Ophionotus
victoriae has been observed to respond to contact by the larger brittle star Ophiosparte gigas by quickly fleeing (7.8).
If successful in capture, Ophiosparte gigas holds the disc of Ophionotus victoriae under its own and clips off arms
to ingest [7].

References: 1:
Polar Biology
3(3):127-139,
1984; 2:
Adaptations
within Antarctic
Ecosystems,
Proceedings of
the Third SCAR
Symposium on
Antarctic
Biology. GA
Llano, ed.
Washington,
DC: Smithsonian
Institution, 1977.
pp.293-326; 3:
The Fauna of the
Ross Sea, Part 1,
Ophiuroidea. HB
Fell. New
Zealand
Department of
Scientific and
Industrial
Research
Bulletin 142,
New Zealand
Oceanographic
Institute Memoir
18, 1961; 4:
Fauna der
Antarktis. J Sieg
& JW Wagele,
eds. Berlin: P.
2 “i a . 7: ‘ Parey, 1990; 5:
os 1 PPS shige Peek: : OVE: Es AFJ Madsen.
Ra Dna Yi, Bs ke tig B.A.N.Z.
: P Antarctic
Research
Expedition
1929-1931.
Reports, Series
B (Zoology and
Botany) Volume
9, Part 3,
Ophiuroidea.
Adelaide:
BANZAR
Expedition
Committee,
1967; 5:
Equinodermos
Antarticos. III.
Ofiuroideos. 1.
Ofiuroidoes del
Extremo Norte
de la Peninsula
Antartica. I
Bernasconi and
MM D'Agostino.
Revista del
Museo
Argentino de
Ciencias
Naturales
"Bernardino
Rivadavia" e
Instituto
Nacional de
Investigacion de
, las Ciencias
Naturales. Hidrobiologia 4(2):81-133 and plates, 1974; 6: Echinodermata from the Palmer Archipelago, South Shetlands, South Georgia and the Bouvet Island... . JA Grieg.
Oslo: I Kommisjon Hos Dybwad, 1929. Scientific Results of the Norwegian Antarctic expeditions, 1927-1928 and 1928-1929 No. 2. Norske Videnskaps-Akademi i Oslo No.
2; 7: Polar Biology 16(5):309-320, 1996; 8: Norbert Wu, personal communication, 1999; 9: Okologie und Populationsdynamik Antarktischer Ophiuroiden (Echinodermata),
Ecology and Population Dynamics of Antarctic Ophiuroids (Echinodermata). C Dahm. Berichte zur Polarforschung, Reports on Polar Research 194, 1996; 10: Molecular
Ecology 32(13):3382-3402, DOE 10.1111/mec.16951

i

129

brittle star Ophioplinthus sp., probably Ophioplinthus gelida

Shown here on a lacy bryozoan, this Ophioplinthus sp. is probably Ophioplinthus gelida which is the most common
member of the genus in McMurdo Sound |3). Dorsal photos are inadequate for distinguishing O. gelida from other
species [3]. Ophioplinthus gelida is found throughout Antarctica and the Antarctic Peninsula, South Shetland
Islands, South Sandwich Islands, and Bouvet Island in depths from 40 to 2,725 meters (2,4,5,6.8,11).

The pentagonal or rounded-pentagonal disc of Ophioplinthus gelida is flattened and up to 2 centimeters in diameter
(2). The arms of O. gelida are long and tapering and reach a length of six centimeters (2,6). O. gelida is colored
orange-brown or yellowish-brown 2}.

ON GS bat. Wu.

Predators of Ophioplinthus gelida include the brittle star Ophiosparte gigas {7|. The maximum age of O. gelida has
been estimated at 33 years [9.

Ophioplinthus gelida captures prey or feeds by moving surface sediments into small mounds which are partially or
completely engulfed; this feeding behavior gathers small organisms as well as eggs and fecal material [1]. O. gelida
feeds on diatoms, silicoflagellates, bryozoans, tunicates/ascidians, foraminifera, polychaetes, gastropods,
polychaetes, sponges, bivalve molluscs, amphipods, and euphausiid krill [1,9).

132

Some Ophioplinthus species may be
parasitized by an epizoic sponge Jophon
radiatum (2). I. radiatum is dark brown,
obscures the brittle star's true color, and
grows on the disc and arm bases of
Ophioplinthus (2). Presence of I.
radiatus is not definitive for identifying
O. gelida; some O. gelida lack it and
other species of Ophioplinthus have it
[2.3.5].

Taxonomic Note: Ophiurolepis genus was synonymized into Ophioplinthus {10}.

References: 1: Adaptations within Antarctic Ecosystems: Proceedings of the Third SCAR Symposium on Antarctic Biology. George A.
Llano, ed. Washington: Smithsonian Institution; Houston, Tex.: distributed by Gulf Pub. Co., 1977. pp.293-326; 2: The Fauna of the Ross
Sea, Part 1, Ophiuroidea. HB Fell. New Zealand Department of Scientific and Industrial Research Bulletin 142, New Zealand
Oceanographic Institute Memoir 18, 1961; 3: John Dearborn, personal communication, 1999; 4: Fauna der Antarktis. J Sieg & JW
Wagele, eds. Berlin: P. Parey, 1990; 5: AFJ Madsen. B.A.N.Z. Antarctic Research Expedition 1929-1931. Reports, Series B (Zoology and
Botany) Volume 9, Part 3, Ophiuroidea. Adelaide: BANZAR Expedition Committee, 1967; 6: Equinodermos Antarticos. HI. Ofiuroideos.
1. Ofiuroidoes del Extremo Norte de la Peninsula Antartica. I Bernasconi and MM D'Agostino. Revista del Museo Argentino de Ciencias
Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales. Hidrobiologia 4(2):81-133 and plates,
1974; 7: Polar Biology 16(5):309-320, 1996; 8: Tethys 6(3):631-653, 1974; 9: Okologie und Populationsdynamik Antarktischer
Ophiuroiden (Echinodermata), Ecology and Population Dynamics of Antarctic Ophiuroids (Echinodermata). C Dahm. Berichte zur
Polarforschung, Reports on Polar Research 194, 1996; 10: Marine Biology Research 4(1-2):76-111, 2008; 11: Polar Biology 38:799-813,
2015

133

brittle star Ophiosparte gigas

Ophiosparte gigas is found throughout Antarctica and the Antarctic Peninsula at depths from 8 to 1,200 meters
[1,2,3,4,5].

134

©Norbert. wu

The disc of Ophiosparte gigas is thick, mucus-covered, convex, and up to seven centimeters in diameter; its large
disc relative to the arms makes it easy to recognize [1,45]. The arms of Ophiosparte gigas have spatulate arm spines,
conical tube feet, and are up to seventeen centimeters long [1.4.5].

Ophiosparte gigas is colored pink, deep pink, pinkish orange, deep reddish, purplish brown, or brick red [1,4,5}.

135

Ophiosparte gigas lives on soft substrate; its movement is made more efficient by its paddle-like arm spines and
stilt-like tube feet (1.

Canadian Museéiin- S8e

=

4

Ophiosparte gigas is an
active benthic predator
on large prey, primarily
brittle stars (including its
own species,
Ophiurolepis gelida,
Ophionotus victoriae,
Ophiacantha sp.,
Ophiocten sp.), bivalves
(including Adamussium
colbecki, Aequiyoldia
eightsti, Yoldiella
sabrina), polychaete
worms, crustaceans,
and sponges [2,5]. O.
gigas also preys on
diatoms, algae,
foraminifera, hydroids,
nematodes, gastropods
(including Nacella
concinna), sea spiders,
ostracods, mysids,

amphipods, isopods, euphausiids (including Euphausia crystallorophias, Euphausia superba), the shrimp Chorismus
antarcticus, bryozoans, cheilostomes, the crinoid Promachocrinus kerguelensis, seastars, and sea urchins (including

Sterechinus neumayeri) (5).

137

eBruce A Miller

The brittle star Ophionotus victoriae has been observed to respond to Ophiosparte gigas contact by quickly fleeing
(5.6]. If successful in capture, Ophiosparte gigas holds the disc of Ophionotus victoriae under its own and clips off
arms to ingest [5].

Ophiosparte gigas is also a scavenger [2,5].

References: 1: The Fauna of the Ross Sea, Part 1, Ophiuroidea. HB Fell. New Zealand Department of Scientific and Industrial Research
Bulletin 142, New Zealand Oceanographic Institute Memoir 18, 1961; 2: Adaptations within Antarctic Ecosystems: Proceedings of the
Third SCAR Symposium on Antarctic Biology. George A. Llano, ed. Washington: Smithsonian Institution; Houston, Tex.: distributed by
Gulf Pub. Co., 1977. pp.293-326; 3: Jim Mastro, personal communication, 1999 [10 meters at Explorer's Cove in New Harbor]; 4:
Equinodermos Antarticos. III. Ofiuroideos. 1. Ofiuroidoes del Extremo Norte de la Peninsula Antartica. | Bernasconi and MM D'Agostino.
Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias
Naturales. Hidrobiologia 4(2):81-133 and plates, 1974; 5: Polar Biology 16(5):309-320, 1996; 6: Norbert Wu, personal communication,
1999

138

sea cucumber Staurocucumis liouvillei

Staurocucumis liouvillei has been collected in
Antarctica and the Antarctic Peninsula and
Bouvet Island, Heard Island and South
Georgia Island from 60 to 791 meters depth
(2,3,5]. S. liouvillei has been collected at sizes
up to eight centimeters long [1,5].

=” Staurocucumis liouvillei lives attached to

sponges, gorgonians (as shown here), and
large stones [4].

139

©Adam G Marsh

Taxonomic Note: In earlier literature, it may appear under the genera Cucumaria or Abyssocucumis [1,3,5}.
Staurocucumis liouvillei is a species complex comprising several discrete species [6].

References: 1: S Ekman. Holothurien. Further Zoological Results of the Swedish Antarctic Expedition 1901-1903. Volume 1, Number 6.
Stockholm: PA Norstedt & Soner, 1925; 2: Berichte zur Polarforschung 41:1-87, 1988; 3: Tethys 5(4):601-610, 1974; 4: Polar Biology
11(3):145-155, 1991; 5: Memoirs of Museum Victoria 59(2):297—325, 2002; 6: Polish Polar Research 34(1):67-86, 2013

sea cucumber Staurocucumis turqueti

Staurocucumis turqueti is found in Antarctica and the Antarctic Peninsula and South Orkney Islands from 10 to 385
meters depth :245s S.turqueti has been collected at lengths up to thirty centimeters ,;,

Staurocucumis turqueti is chestnut or brown colored [1,2).

OSI Hat ees

Staurocucumis turqueti is a suspension feeder and has been observed on the sediment surface holding the anterior
half of its body vertically up in the water to suspension feed |S. turqueti has been observed attached to sponges («,

Taxonomic Note: Appears under other genera in the older literature including Abyssocucumis, Cucumaria and
Ekmocucumis (23,4,7|. Staurocucumis grandis 1s a synonym of S. turqueti {9}.

References: 1: C Vaney. Holothuries. Expedition Antarctique Francaise (1903-1905). Paris: Masson et Cie, 1906; 2: S Ekman.
Holothurien. Further Zoological Results of the Swedish Antarctic Expedition 1901-1903. Volume 1, Number 6. Stockholm: PA Norstedt &
Soner, 1925; 3: Julian Gutt, personal communication, 1999; 4: Tethys 5(4):601-610, 1974; 5: Berichte zur Polarforschung 41:1-87, 1988;
6: Polar Biology 11(3):145-155, 1991; 7: Memoirs of Museum Victoria 59(2):297—325, 2002; 8: Polar Biology 38:799-813, 2015; 9:
Zootaxa 2016(1):1-16, 2009

143

sea cucumber Bathyplotes bongraini

TeNforber tain

Bathyplotes bongraini is found throughout Antarctica and the Antarctic Peninsula and Bouvet Island at depths from
4.5 to 768 meters [1,3,4,5.6,7,8]. B. bongraini has been collected at lengths up to 26 centimeters [1,6). B. bongraini is
usually colored dark pink with a distinct dark brown cross-band, two to three centimeters wide, slightly behind the
middle of the body (11.
tha © Jim Mastro

The dorsal conical papillae of Bathyplotes
bongraini are 1-5 millimeters high [1).

B. bongraini is a sediment feeder 2]. The
mouth of B. bongraini is turned down
(ventrally) and its anus is subdorsal [1).

Taxonomic Note: Older species name was fuscivinculum (6).

References: 1: Zoologica Scripta 19(1):119-127, 1990; 2: Polar Biology 11(3):145-155, 1991; 3: Jim Mastro, personal communication
(New Harbor 21 & 28 meters [photo]; Hutton Cliffs 4.5 meters), 1999; 4: Peter Brueggeman, personal communication (New Harbor 26
meters), 1999; 5: Polar Biology 20(4):229-247, 1998; 6: Memoirs of Museum Victoria 59(2):297-325, 2002; 7: Polar Biology 29(2):83-
96, 2006; 8: Polar Biology 38:799-813, 2015

144

sea cucumber Cucumaria spp.

These Cucumaria spp. sea cucumbers are impossible to identify to the species level from this photo [1). Even with
specimens on hand, identification is difficult; the literature of this group is confusing, and they have been referred
to as Cucumaria georgiana-group [1,2].

Cucumaria spp. has been observed attached to sea urchins, branched bryozoans, and hydroid stalks {2}. Here
Cucumaria spp. sea cucumber is perched on algae Phyllophora antarctica on top of the sea urchin Sterechinus
neumayeri.

References: 1: Julian Gutt, personal communication, 1999; 2: Polar Biology 11(3):145-155, 1991

145

sea cucumber Echinopsolus acanthocola

Echinopsolus
acanthocola has
been collected in the
Weddell Sea and
Bouvet Island at
depths from 177 to
650 meters ,14;7. Here
it is photographed at
scuba diving depth in
McMurdo Sound. E.
acanthocola has
scattered peaked
cone-shaped
processes on its body
wall and its color is
rose to brownish-red
[1,6]+

Echinopsolus
acanthocola is a
suspension feeder
and has a narrow
sole delimited by
tube feet, which
restricts it to using
narrow, rod-like
structures as
substrate; it has been
collected attached to
sea urchin spines pq).
Here E. acanthocola
is attached to the sea
urchin Sterechinus
neumayeri and it has
been collected
attached to the pencil
urchin Ctenocidaris
perrieri \3),

Echinopsolus acanthocola has been collected at
lengths up to 2.3 centimeters long 11,.

147

© Bruce A. Miller

The species name acanthocola is
composed of Colere (meaning "to
inhabit") and Acantha (meaning
"spine, thorn") to indicate that this
sea cucumber species is well
adapted to live on sea urchin
spines and similar structures ,,,.

References: 1: Zoologica Scripta 19(1): 101-117, 1990; 2: Polar Biology 11(3):145-155, 1991; 3: Bulletin de l'Institut Royal des Sciences
Naturelles de Belgique, Biologie 62:179-191, 1992; 4: Polar Biology 29(2):106-113, 2006; 5: Polar Biology 38:799-813, 2015; 6: Zootaxa
3841(4):573-591, 2014; 7: Zootaxa 2196:1-18, 2009

148

sea cucumber Heterocucumis steineni

©Peter Brueggeman

Heterocucumis steineni is found in Antarctica and the Antarctic Peninsula, South Shetland Islands, South Orkney
Islands, South Georgia Island, Falkland Islands, and Burdwood Bank from 0 to 1,200 meters depth [2.3.5]. H. steineni
is beige to chestnut brown, can be almost white or white and brown in one specimen, and has dark spots between
tentacles [1,56]. H. steineni is up to fifteen centimeters long (2).

149

ONombert Wu

Heterocucumis steineni may attach to other organisms like hydroids and fan-shaped bryozoans or it may live with

the lower half of its body in sediment (4,7). This facultative lifestyle may explain why its posterior feet are wart-like
and its anterior feet are exceptionally long, up to five millimeters (4,7).

150

© Peter Brueggeman

Heterocucumis steineni is a suspension
feeder [4,7].

Heterocucumis steineni is one of the most
widely spread Dendrochirotida sea
cucumbers in the Weddell Sea 14}.

Taxonomic Note: In earlier literature, appears under different genera including Cucumaria, Ekmocucumis, and
Heterocucumis {8}.

References: 1: C Vaney. Holothuries. Expedition Antarctique Francaise (1903-1905). Paris: Masson et Cie, 1906; 2: S Ekman. Holothurien. Further Zoological Results of
the Swedish Antarctic Expedition 1901-1903. Volume 1, Number 6. Stockholm: PA Norstedt & Soner, 1925; 3: Berichte zur Polarforschung 41:1-87, 1988; 4: Polar Biology
11(3):145-155, 1991; 5: Fauna der Antarktis. J Sieg, JW Wagele, eds. Berlin: P Parey, 1990; 6: Julian Gutt, personal communication, 2000; 7: Polar Biology 11(8):533-544,
1992; 8: Memoirs of Museum Victoria 59(2):297—325, 2002; 9: Polar Biology 38:799-813, 2015

151

sea cucumber, group Aspidochirotida

Taxonomic Note: Not Staurocucumis turqueti (x.

References: 1: Julian Gutt, personal communication, 2000

152

crinoid Promachocrinus kerguelensis

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©Norbert Wy,

Promachocrinus kerguelensis is found throughout Antarctica and the Antarctic Peninsula, South Shetland Islands,
South Georgia Island, Bouvet Island, Kerguelen Island, and Heard Island, from 10 to 2,100 meters depth [3,4.6,9}. P.
kerguelensis is also found in the Strait of Magellan, and between Australia/New Zealand and the Antarctic

continent ([3,4,7].

153

©Adam G. Marsh

Promachocrinus kerguelensis has ten biradiate rays (20 arms), is the most widely distributed and abundant crinoid

in Antarctica and subantarctic islands, is the largest comatulid (unstalked) crinoid in southern latitudes and is the
only 20-armed comulatid crinoid in high southern latitudes [3,4,9}.

154

Promachocrinus kerguelensis can be solid colored or banded; its color ranges from ivory to buff with light to dark
brown pinnules and if banded, the bands can be dark to reddish brown j3,4}. Individuals from the Ross Sea may be
more uniform in color; solid color and banded specimens can occur in the same population [4}.

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The arms of Promachocrinus kerguelensis are edged with feathery pinnules containing sensory tube feet and
reproductive organs. The arms are used to trap drifting plankton and they have grooves down which food particles
are carried by hair-like cilia to the upward-facing mouth. Its different feeding postures (a filtration fan, a radial
posture with its pinnules in one plane, and a collecting bowl) are suggested as a response to ocean currents [3].

156

Promachocrinus kerguelensis produces large numbers of buoyant eggs which spawn into the plankton in November
and December in McMurdo Sound; it doesn't brood eggs in its arms as do some Antarctic crinoids ,1). Settlement of

its free-floating larvae occurs 2 to 3 months later when the seasonal Antarctic plankton bloom is high and offers a
rich food source [1}.

Promachocrinus kerguelensis (and other comatulid crinoids) cling and move by walking on specialized curved
structures called cirri (seen at lower left). P. kerguelensis clings to sponges, worm tubes, gorgonians, and rocks as

well as mud and gravel |2,3}. This gives P. kerguelensis a high perch above the seafloor which may protect it from
fish nibbling on its extended arms [2).

158

Promachocrinus kerguelensis is not toxic to fish, but there are no Antarctic fish living in the water above the
seafloor to nibble at its arms ,2}. The predatory brittle star Ophiosparte gigas has been found to have P. kerguelensis
in its gut contents [5].

Taxonomic Note: Genetic analysis shows that Promachocrinus kerguelensis may be comprised of two cryptic
species [sg].

References: 1: Marine Biology 96(3):375-383, 1987; 2: Polar Biology 9(7):461-465, 1989; 3: Biology of the Antarctic Seas XIII. Louis S.
Kornicker, ed. Antarctic Research Series Volume 38. Washington, DC: American Geophysical Union, 1983. pp.1-60; 4: Comatulid
Crinoids from R/V Eltanin Cruises in the Southern Oceans. Janis A. Speel. University Of Maine PhD dissertation. 1976; 5: Polar Biology
16(5):309-320, 1996; 6: Tethys 6(3):631-653, 1974; 7: Revista Ciencia y Tecnologia del Mar 29(1):91-102, 2006; 8: Molecular Ecology
21(10):2502-2518, 2012; 9: Diversity 15: 875, 2023 doi.org/10.3390/d15070875

139